The following are some of the mangrove areas in Sri Lanka:

1. Rekawa Lagoon – Located in the southern coast of Sri Lanka, it is a wetland complex that supports a diverse range of mangrove species, including Rhizophora mucronata, Avicennia marina, and Sonneratia caseolaris.
2. Maduganga Estuary – This is a Ramsar wetland site located in the southwestern part of Sri Lanka. It is a unique ecosystem with a mix of freshwater and seawater, and supports a variety of mangrove species, including Rhizophora mucronata, Avicennia marina, and Bruguiera gymnorrhiza.
3. Muthurajawela Marsh – This is a coastal wetland located in the western coast of Sri Lanka, and it is home to several mangrove species, including Rhizophora mucronata, Avicennia marina, and Lumnitzera racemosa.
4. Pambala Lagoon – Located in the northwestern part of Sri Lanka, it is a shallow estuarine lagoon that supports several mangrove species, including Rhizophora mucronata, Avicennia marina, and Sonneratia caseolaris.
5. Puttalam Lagoon – This is a large estuarine lagoon located in the northwestern part of Sri Lanka, and it supports a variety of mangrove species, including Rhizophora mucronata, Avicennia marina, and Bruguiera gymnorrhiza.

Overall, mangroves cover about 19, 894 hectares of land area in Sri Lanka, and they provide important ecosystem services such as coastal protection, carbon sequestration, and habitat for various marine and terrestrial species.